A burning log in the fireplace may produce a pleasant smell, but this method of warming a home in the winter may present risks to people with respiratory problems. Smoke, whether from wood, coal or tobacco products, gives off particles in the air that are considered household air pollutants.

A new five-year study looks at how those airborne particles affect patients with chronic obstructive pulmonary disease, or COPD, who live in rural and urban areas. The patients will be visited three times over a span of six months, and monitors will be placed in their homes to look for toxins in the air. Dr. Mildred Maisonet, a professor at East Tennessee State University, leads the rural side of the study.